Unit 1 Flashcards
What is an activated complex?
The unstable arrangement of atoms formed at the max of potential energy barriers.
What is the activation energy?
The minimum kinetic energy required by colliding molecules for a reaction to occur.
Define exothermic.
Gives out heat, the enthalpy of the products is less than that of the reaction
What is endothermic?
Cold, enthalpy of the products is more than that of the reaction
How do impurities in a reaction mixture decrease the efficiency of a catalyst?
They adsorb onto the surface of the catalyst and remove potential sites for gas molecules to react.
What is adsorption?
When molecules from the reactant form bonds with the catalyst therefore weakening the bonds within the molecule.
What is desorption?
When the product molecules leave the catalyst and a vacant site can be occupied by another reactant molecule.
Which bond needs there to be a large difference in electronegativity?
Ionic bond
Give some characteristics of covalent networks
Hardness, high melting points, strong bonds
Define covalent bond
The sharing of 2 electrons (one from each atom) to complete the outer shell of electrons.
Most _________ substances are discrete molecules
Covalent
Give some characteristics of metallic bonds
Delocalised electrons
Lattice is formed when the structure is made from positive ions
It is the electrostatic force of attraction between positively charged ions and delocalised electrons
Describe a chemical test that could be carried a out on a hydrocarbon solution to determine whether it’s saturated or unsaturated?
Use bromine water, if it stays clear it is unsaturated
What’s the weakest of all intermolecular forces?
London dispersion forces
Describe permanent dipole-permanent dipole interactions
The electrons are pulled to one side of the molecule
One side slightly positive, one side slightly negative
